Squitieri hemodialysis and vascular access systems

ABSTRACT

A hemodialysis and vascular access system comprises a subcutaneous composite PTFE silastic arteriovenous fistula having an indwelling silastic venous end which is inserted percutaneously into a vein and a PTFE arterial end which is anastomosed to an artery. Access to a blood stream within the system is gained by direct puncture of needle(s) into a needle receiving site having a tubular passage within a metal or plastic frame and a silicone upper surface through which needle(s) are inserted. In an alternate embodiment of the invention, percutaneous access to a blood stream may be gained by placing needles directly into the system (i.e. into the PTFE arterial end). The invention also proposes an additional embodiment having an arterialized indwelling venous catheter where blood flows from an artery through a tube and a port into an arterial reservoir and is returned to a vein via a port and a venous outlet tube distinct and distant from the area where the blood from the artery enters the arterial reservoir. The site where blood is returned to the vein is not directly fixed to the venous wall but is free floating within the vein. This system provides a hemodialysis and venous access graft which has superior longevity and performance, is easier to implant and is much more user friendly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/219,998 filed on Aug. 15, 2002, which is a reissue of U.S.application Ser. No. 08/835,316 filed on Apr. 7, 1997, now U.S. Pat. No.6,102,884, which claims benefit under 35 U.S.C. Section 119(e) to U.S.Application No. 60/037,094, filed on Feb. 3, 1997, all of which areincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Currently, HD (hemodialysis) and vascular access for chemotherapy andplasmapheresis is achieved in one of several ways. Applicant's inventioninvolves a new method and instrumentation for HD and vascular accessdesigned to eliminate the problems of the prior methods and create anew, more durable, easier to use, vascular access system.

One prior art method involves a primary arteriovenous fistula. In thismethod, a native artery is sewn to a native vein creating a high flowsystem of blood in a vein which over time can be accessed with twohemodialysis needles attached to a dialysis machine. The problem withthis method is that few patients are candidates secondary to anatomy andin others the veins or shunt fail to enlarge and mature properly even ifthe primary fistula remains patent. These arteriovenous fistulas alsobecome aneursymol over time requiring revision.

Another method involves a subcutaneous prosthetic conduit (PTFE) in theshape of a tube which is sewn at either end to openings made in anartery and vein. This method causes recurrent stenosis at the venousoutflow leading to thrombosis (i.e., graft closure) secondary to intimalhyperplasia at venous anastomosis. Thrombosis also occurs at needlepuncture sites along the PTFE.

Another method involves a “tunneled” percutaneous dual lumen catheterwhich is inserted into a central vein. This causes recurrent thrombosissecondary to stasis of blood in the lumen (i.e., not a continuous flowsystem like an A-V fistula) and build up of fibrinous debris at thevenous end. Further, the access end of the catheter protrudes throughthe skin making it cosmetically unappealing, cumbersome to live with, aswell as more likely to become infected.

A further method involves the use of the Sorenson Catheter. This is apercutaneous (not tunneled) dual lumen catheter, placed into the centralvenous system, which is used to provide temporary access for thepurposes of hemodialysis. These catheters are prone to kinking,clotting, infection, and poor flow rates.

A still further method of vascular access involves the “Port-a-cath”.This system of venous access, which utilizes a subcutaneous reservoirattached to a central venous catheter, is used for long term intervenousaccess for chemotherapy etc. (It is not intended for HD.) The ports areprone to clotting and must be continually flushed since they are astagnant system.

Applicant's invention involves a vascular access system, known as theSquitieri Hemodialysis and Vascular Access System, which creates acontinuous blood flow and which is easily accessed and resistant toclotting. These advantages provide ideal access for long term HD chemoor blood draws. An example, would be patients who are on coumadin whichrequire weekly blood draws. This new system becomes less painful overtime as the skin over the “needle access” site become less sensitive.The veins are spared repeated blood draws which results in veinthrombosis to such a degree that some patients “have no veins left”making routine blood draws impossible.

Among the more relevant prior art patents are U.S. Pat. Nos. 4,898,669,4,822,341; 5,041,098; and, 4,790,826. None of the foregoing patentsdisclose a system having the features of this invention. U.S. Pat. No.4,447,237 describes improvements in a valving slit which includes theprovision of a flattened sleeve within an elastomeric body presentingopposed interior surfaces interengaged when the valving slit is in theclosed condition and spaced apart when the valving slit is in the opencondition.

SUMMARY OF THE INVENTION

A hemodialysis and vascular access system comprises a PTFE end which issutured to an opening in an artery at one end and the other end isplaced into a vein using any technique which avoids the need for ananastomosis between the silicone “venous” end of the catheter and thevein wall. The system comprises any material, synthetic or natural (i.e.vein) which can be sutured to the artery (i.e. preferably PTFE) at oneend while the other end is composed of a material which is suitable forplacement into a vein in such a way that the openings in the “venous”end of the system are away from the site where the graft enters thevein. The system may also be constructed of multiple layers of materialsi.e. PTFE on the inside with silastic on the outside. The “NeedleReceiving Site” may also be covered with PTFE to encourage self sealingand tissue in-growth.

A preferred embodiment comprises a combination of PTFE conduit sewn toan artery on one end of the system with the other end connected to asilastic-plastic catheter which can be percutaneously inserted into avein via an introducer. The venous end may also be placed via open cutdown. The seal around the system where it enters the vein may be “selfsealing” when placed in percutaneous technique; it may be achieved witha purse string when done by open technique “cut down”; or, it may besewn to the vein to create a seal with a “cuff” while the systemcontinues downstream within the venous system to return the arterialblood away from the site of entry into the vein. The entire system canbe positioned subcutaneously at the completion of insertion. This designis a significant improvement over existing methods because it avoids themost frequent complication of current HD access methods. By utilizing anindwelling venous end, one avoids creating a sewn anastomosis on a veinwhich is prone to stenosis secondary to neointimal hyperplasia. Byhaving continuous flow through the silastic end of the catheter,thrombosis of these catheters can be avoided. Dialysis is made moreefficient by decreasing recirculation of blood which accompanies the useof side by side dual lumen catheters inserted into a central vein. Thisinvention not only benefits the patient but it also speeds dialysis thussaving time and money.

To summarize, the Squitieri Access System comprises a tube composed ofPTFE and a silastic catheter. This tube is used to create anarteriovenous fistula. The PTFE end (arterial end) of the tube is sewnto an artery while the silastic catheter end is placed into the venoussystem by the Seldinger technique much like a standard central line. Theentire system is subcutaneous at the completion of insertion. Thissystem is a composite of the arterial end of a “gortex graft” joined tothe venous end of a “permacath”. This system enjoys strengths of eachtype of access and at the same time avoids their weaknesses.

Accordingly, an object of this invention is to provide a new andimproved vascular access system.

Another object of this invention is to provide a new and improvedhemodialysis and vascular access system including an easily replaceableneedle receiving site which has superior longevity and performance, ismore easily implanted, more easily replaced, and is “user friendly” i.e.easily and safely accessed by a nurse or patient which is ideal for homehemodialysis.

A more specific object of this invention is to provide a new andimproved Squitieri hemodialysis and vascular access system including asubcutaneous composite PTFE/Silastic arteriovenous fistula.

A further object of this invention is to provide a new and improvedhemodialysis and vascular access system including a fistula utilizing anindwelling silastic end which is inserted percutaneously into the venoussystem and a PTFE arterial end which is anastomosed to an artery andincluding a unique needle receiving sites which are positioned anywherebetween the ends and which have superior longevity and performance.

A further object of this invention is to provide a system constructed topreserve laminar flow within the system and at the venous outflow end toreduce turbulence and shear force in the vascular system to the degreepossible.

A still further object of this invention is to provide a system whereinthe arterial end (PTFE) may also be placed by percutaneous techniqueincluding one where blood entry holes are distant from the site whereblood enters the veins.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects of this invention may be more clearly seenwhen viewed in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of the vascular access system comprisingthe invention;

FIG. 2 is a cross-sectional view of the needle access site taken alongthe line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view similar to FIG. 2 with a needleinserted into the access site;

FIG. 4 is a cross-sectional view of the coupling between the PTFE andthe silicone venous end of the catheter;

FIG. 5 is a perspective view of an alternate embodiment of the inventionwith one port having a tube sewn to a vein;

FIG. 6 is a perspective view of the embodiment in FIG. 5 with a silastictube floated down a vein;

FIG. 7 illustrates a ringed tube sewn to an artery and connected to afirst access site which is joined to a second site by silastic tubingand includes an outflow through silastic tubing which is floated intothe venous system;

FIG. 8 is similar to FIG. 7 but shows PTFE sewn to an artery andsilastic tubing floated into a different portion of the venous system;

FIG. 9 depicts ringed PTFE tubing sewn to the subclavian artery and adual access site coupled to the venous system at its other end;

FIG. 10 shows a multi-layered variation at the venous end of the system;

FIG. 11 discloses a quick coupler design utilized in conjunction withthe system;

FIG. 12 is a unique port design utilized in conjunction with the system;

FIG. 13 shows holes where ports can be fixed in place while FIG. 13 aand FIG. 13 b show cross-sectional views which depict the internalconstruction of the invention with FIG. 13 b illustrating multi-layeredtubing; and,

FIG. 14 shows a variation of the system entry through vein wall (i.e.not percutaneous or purse string) wherein a cuff, sewn to vein asindwelling portion, is floated down stream.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings the Squitieri hemodialysis and vascularsystem, as shown in FIG. 1, comprises a PTFE/Dacron (or other syntheticor natural material) tube 10 of several centimeters in length which isattached at one end by means of a coupling to a needle access site orreceiving site 20. Adjustable band 18 regulates the blood flow throughthe access site 20. The PTFE tube 10 is approximately 7 mm in diameterand transitions downward to an open end portion 19 approximately 4 mm indiameter.

The access site 20 includes an in line aperture 16, see FIG. 2, having asilicone tube 41 connected thereto at one end leading to a long flexibleplastic/silastic/silicone tube 12 with transverse holes 13 along itsfree end. The number of holes 13 may vary within predetermined limits toachieve optimum results. The end 36 may be beveled for ease ofinsertion. This tubular arrangement functions as a subcutaneousconnection between the arterial and venous systems. It may also bemodified to allow part of the system to exit through the skin 14 (FIG.3) to provide access to the blood circulation without placing needles 15(FIG. 3) through the skin 14 into the fistula (usually at the PTFE end).

Along the length of the catheter specially constructed needle accesssites 20 (FIGS. 1, 7, 8, and 10) are located to receive speciallydesigned needles 15 into the system to gain access to the blood streamwhich flows through aperture 16. This method avoids perigraft bleedingwhich leads to thrombosis either by compression of the graft by hematomaor by manual pressure applied to the graft in an attempt to control thebleeding.

The needle access areas 20 which are designed to receive needles 15 etc.to allow access to the system are in line conduits with self-sealingmaterial 25 which is here shown as a silicone member 25 which can belocated beneath the skin surface. The silicone member 25 comprises anoval configuration exposed within the frame 26 for ease of puncture. Thesystem may be accessed immediately after insertion without having towait for the graft to incorporate into the tissues as is the case withthe current methods of subcutaneous fistulas. These access areas 20 willprotect the graft since they are uniformly and easily utilized requiringlittle training or experience. The “needle receiving” sites 20 aredesigned in such a way to preserve laminar flow as far as possible (i.e.not a reservoir arrangement). Needle receiver sites 20 may be connectedto a system via “quick couple” 45 for easy exchangability, see FIG. 11.

FIGS. 2 and 3 disclose a needle access site 20 wherein a silicone member25 is mounted within a plastic or metal frame 26. A protruding portion27 of member 25 extends upwardly through the aperture 31 while a flangeportion 28 extends outwardly on both sides of the portion 27 to begripped by teeth 29 on the internal surface of frame 26 and member 32.The frame 26 includes an in-line aperture or passage 16 through theneedle access site 20 for blood flow. The blood flow is accessed byinserting needles 15 through the silicone member 25 which is preferablyoval in shape. The teeth 29 seal the arterial pressure. The passage 16of the needle receiving site 20 is tubular in shape.

The open end portion 19 of the PTFE tube 10 is sewn to an opening in anartery 30, see FIGS. 5, 6, 7, 8 and 9, while the flexible plastic tube24 of the system having been inserted percutaneously lies in the venoussystem in such a way that the openings 13 in the silastic tube 12 aredownstream from the site where the flexible plastic tube 24 enters thevein 40 (see FIGS. 5 and 6). The venous end may be inserted via“cutdown”. The purpose of the system is to allow communication betweenan artery 30 and a vein 40 in such a way that the system may be accessedby either puncturing the PTFE segment or by entering the specialized“needle receiving” site 20. This allows blood to flow from the system toa hemodialysis (HD) machine (not shown) and then return into the venousoutflow portion at a more distal (venous end) location allowing theblood to return from the HD machine (not shown) back into the patient.

FIG. 4 discloses, as an alternative, a “glued” connection between PTFEtubing 60 and silicone tubing 61 wherein the PTFE tubing 60 is insertedinto an enlarged portion of silicone tubing 61 wherein thelongitudinally extending portion includes a raised section 63 whichlocks a raised section 64 of PTFE tubing 61 within the silicone tubing61.

In this invention, the materials used may vary as specified herein. Thesystem may be constructed of one or more specific materials. Thearteries and veins used may also vary. Material may also be covered withthrombus resistant coatings (heparin, etc.) or biologic tissue. Thesystem may in specific cases be “ringed” for support.

The same concept of using an arterialized venous access catheter may beapplied to the use of long term indwelling catheters used to givechemotherapy etc., making the current ports obsolete as these new accesssystems will have a decreased thrombosis rate and they will no longerneed to be flushed as continuous blood flow through the system makesthrombus formation unlikely. This will definitely cut down on costssince it will decrease nursing requirements in out patient settings,etc.

In alternate embodiments shown in FIGS. 5 and 6, the system comprises anarterial reservoir structure or port 50 with needle accessible topportions 51 a and 51 b, each of which a preferably-constructed ofsilicone. The arterial reservoir structure 50 is connected to an outlettube 53 of PTFE (gortex-ringed), which is sewn to an artery 30 at itsother end. The venous outlet tube portion 57 is constructed in a similarway but it is either sewn to a vein 40 via gortex ringed portion 52 oris placed percutaneously into the central circulation via an indwellingvenous (silicon) catheter 42 as shown in FIG. 6. There is no continuousflow through this version of the system since the ports are notconnected. Flow is established when the system is attached to an HDmachine with a needle 15 in the arterial port 51 a to deliver blood tothe HD machine and a second needle 15 is placed in the venous port 51 bto the vein 40 to deliver blood to the patient. The ports 51 a, 51 bwill remain flushed with heparin when not in use to avoid clotting whenaccessed through the skin 14 with needles 15. The ports 51 a, 51 b willalso provide high flow access to both the arterial and venous systems.FIG. 6 shows two separate ports 51 a and 51 b with the outlet tube 53sewn to an artery 30 and the indwelling venous catheter 42 floated downa vein 40.

FIG. 7 illustrates, in an anatomical drawing, an outlet tube 53 of PTFE(ringed gortex) sewn to an artery 30 at 62 and coupled at its other end62 a to the needle access site 20. The site 20, see FIGS. 1-3, is joinedby silastic tubing 68 to a second access site 20 a which has an outletsilastic tube 65. The outlet tube 65 includes a plurality ofperforations 66 at its outlet end which is positioned in the venoussystem 67 through vein 40. Either site 20 or 20 a can be used for needleaccess.

FIG. 8 depicts an embodiment similar to that of FIG. 7 except that thecoupling between the artery 30 and the first needle access site 20 isPTFE tube 69. The entry to the venous system 67 is via vein 40 which hassilastic tubing 65 floated therein. A PTFE tube portion 69 a joins parts20 and 20 a.

FIG. 9 illustrates a dual needle access site 80 which is coupled viaoutlet tube 53 of PTFE (gortex-ringed) to the subclavian artery 30 andfloated into the venous system 67 via silastic tubing 65. The dual site80 provides additional access through 25 a, 25 b in approximately thesame area with tubing (not shown) extending through the dual site needleaccess site 80.

FIG. 10 depicts a variation of the invention at the venous end whereinthe outlet of the port 20 comprises PTFE tubing 91 located within asilastic catheter 92. This design is appropriate if thrombosis is aproblem in the outlet silastic portion of the shunt.

FIG. 11 discloses a quick coupler 45 joining the PTFE outlet tube 53(gortex-ringed) to the port 46 in the needle access site 20. A plasticor metal member 47 includes a portion 48 which engages the cylindricalPTFE tubing 10, an intermediate portion 49 extending perpendicularlyoutward and an end portion 43 tapered outwardly at an angle andincluding an inward projection 44. The projecting portion 44 of themember 47 engages a slot 54 in the port 46 firmly fixing the cylindricalPTFE tubing 10 therebetween. Portion 48 is made of flexible material toallow a gentle curve in tubing as it exits/enters port.

FIG. 12 is an exploded view of a new port embodiment wherein the port 71comprises a frame 72 having an inlet coupling 73 and an outlet coupling74. The plastic or metal frame 72 includes a recessed reservoir 76 andend walls 78 a and 78 b. An upper member 85 having a top or upper member85 a, a recess 83 and downwardly projecting sides 87 a and 87 b fitswithin walls 77 a and 77 b. The upper member 85 includes an ovalsilicone access site 90. The member 45 rapidly couples the PTFE tubing10 to site 71 with tubing 88 which fits over the inlet coupling 73 andthe outlet coupling 74 with recessed portions 75 a and 75 b which engagetubing 88 (only one of which is shown) and have couplers 45 (only one ofwhich is shown) which slide over the tubing 88 to engage the inlet andoutlet couplings 73 and 74.

A housing 86 includes a top portion 86 a and a side portion 86 b. Thetop portion 86 a includes an aperture which surrounds and provides ameans for accessing the oval silicone access site 90. This embodimentprovides a quick assembly for a needle access site 71.

FIG. 13 shows a typical dual port system showing holes 55 where ports 20can be fixed in place, while FIG. 13 a and FIG. 13 b showcross-sectional views which depict the internal construction of theinvention with FIG. 13 b illustrating multi-layered tubing.

FIG. 14 discloses a cuff 56 which is made of PTFE and sewn to a vein. Nophysiological/functional venues anastomosis is created as blood isreturned at the end of the system distant from the cuff. The silasticend 12 may still be lined with PTFE.

The Squitieri Hemodialysis/Vascular Access System avoids creation of avenous anastomosis, a revolutionary advancement, i.e. there is no sitefor neointimal hyperplasia at a venous anastomosis which accounts forthe vast majority of PTFE arteriovenous graft failures (60-80%). This isaccomplished by returning the blood into a larger vein via an indwellingvenous catheter 42. The site of blood return to the venous system is notfixed to the vein wall where neointimal hyperplasia occurs with thestandard PTFE bridge graft. This feature represents a tremendousadvantage over the present grafts.

As a further advantage, the system is not stagnant and prone tothrombosis, i.e. constant flow through the new system avoids the problemof clotting inherent in indwelling dual lumen venous catheters whichremain stagnant when not in use. It also avoids need to flush catheterswith heplock thereby reducing nursing costs to maintain the catheter.

The Squitieri system avoids externalization of components which areprone to infection. Since dual lumen catheters exit the skin 14, theyfrequently lead to sepsis requiring catheter removal despitesubcutaneous tunneling. This new access is entirely subcutaneous.

Very importantly the system proposed herein, avoids problems with theaspiration of blood from the venous system and “positional” placementthrough continuous flow. A frequent problem with dual lumen catheters istheir inability to draw blood from the venous system due to clot andfibrinous debris ball-valving at the tip of a catheter. This new systemreceives blood directly from arterial inflow which ensures high flowrates needed for shorter, more efficient dialysis runs. It also avoidsthe frequent problem of the catheter tip “sucking” on the vein wallinhibiting flow to the dialysis machine and rendering the accessineffective.

The system avoids recirculation seen with dual lumen catheters resultingin more efficient and more cost effective dialysis.

The system avoids the need for temporary access with incorporation of“Needle Access Sites” 20. A-V fistulas and gortex grafts must “mature”for several weeks before use. This creates a huge strain on the patientas well as the doctor to achieve temporary access while waiting to usethe permanent access. Temporary access is very prone to infection,malfunction and vein destruction. By placing sites 20 designed toreceive needles 15 along the new access, the system may be used the dayit is inserted.

The system avoids PTFE needle site damage with the incorporation of“Needle Access Sites” 20. Needle access directly into PTFE is presentlyuncontrolled and user dependent. Often, PTFE is lacerated by accessneedles. While this system may be accessed via the PTFE segment, theneedle receiving sites are the preferred method. This leads to excessivebleeding which requires excessive pressure to halt the bleeding causingthrombosis of the graft. “Needle Access Sites” 20 on the Squitieriaccess system allow safe, quick, and easy entry into the system andavoid the complications inherent in placing needles directly into PTFE.It also avoids perigraft bleeding which will compress and thrombose thegraft. By eliminating the long time needed to compress bleeding at theneedle site, the system shortens dialysis runs.

The Squitieri system permits an easier, faster insertion technique. Onlyone anastomosis the arterial end and a percutaneous placement of thevenous end is required. A modification allows the system to be suturedto the vein wall while the system tubing is floated down stream fromthis site where the system enters the vein 40. This saves operating roomtime at thousands of dollars per hour. The technique is easier withfaster replacement. It avoids difficult and time consuming revision ofvenous anastomosis required to repair venous outflow occluded byneointimal hyperplasia. If the system malfunctions, the silasticcatheter end 65 slips out easily and the arterial end of the outlet tube53 is thrombectomized. New access sewn to the thrombectomized end of theoutlet tube 53 of PTFE at the arterial end and the silastic venous endis replaced percutaneously via Seldinger technique or “open technique”.

The end result of the above advantages translates into superior patencyrates and a decreased complication rate with this new system. Patientsare spared the repeated painful hospitalizations for failed access aswell as the emotional trauma associated with this difficult condition.The physicians are spared the dilemma of how to best treat thesepatients. This system will have a large impact on the current practiceof vascular access in areas such as hemodialysis; plasmapheresis;chemotherapy; hyperalimentation; and chronic blood draws.

While the invention has been explained by a detailed description ofcertain specific embodiments, it is understood that variousmodifications and substitutions can be made in any of them within thescope of the appended claims which are intended also to includeequivalents of such embodiments.

1. A hemodialysis and vascular access system wherein: said systemcomprises a first portion comprising a tube and a second portioncomprising a catheter and wherein: said tube is provided from a materialwhich can be sutured to the artery with a first end of said tube adaptedto be coupled to an artery; and said catheter is adapted to be insertedwithin a vein at an insertion site, with a first end of the catheterhaving an opening adapted to be within the vein itself and wherein theopening in the first end of said catheter is distant from the insertionsite and said tube and said catheter being adapted to be entirelysubcutaneous in use and configured to avoid, in use, a reservoirtherein.
 2. The hemodialysis and vascular access system of claim 1,wherein said system has a single lumen formed by said tube and saidcatheter.
 3. The hemodialysis and vascular access system of claim 1,wherein said first end of the catheter is adapted for percutaneousinsertion.
 4. The hemodialysis and vascular access system of claim 3,wherein said first end of the catheter is beveled.
 5. The hemodialysisand vascular access system of claim 1, wherein a second end of the tubeis adapted to be coupled to a second end of the catheter.
 6. Thehemodialysis and vascular access system of claim 5, wherein said secondend of the catheter comprises an enlarged portion configured to lockwith said second end of the tube.
 7. The hemodialysis and vascularaccess system of claim 5, wherein said system further comprises acoupler adapted to join said second end of the tube to said second endof the catheter.
 8. The hemodialysis and vascular access system of claim5, wherein said second end of the tube is glued to said second end ofthe catheter.
 9. The hemodialysis and vascular access system of claim 1,wherein said catheter comprises a cuff adapted for sewing to the vein.10. The hemodialysis and vascular access system of claim 1, wherein saidcatheter comprises multiple layers of material.
 11. The hemodialysis andvascular access system of claim 10, wherein at least one layer is athrombus resistant coating.
 12. The hemodialysis and vascular accesssystem of claim 10, wherein said catheter further comprises an innerlayer of PTFE material and an outer layer of silastic material.
 13. Thehemodialysis and vascular access system of claim 1, wherein the tubecomprises a PTFE material and the catheter comprises a silasticmaterial.
 14. The hemodialysis and vascular access system of claim 1,wherein said system further comprises a needle receiving site locatedbetween said first end of the tube and said first end of the catheter.15. The hemodialysis and vascular access system of claim 14, wherein theneedle receiving site comprises a frame having a passage extendingtherethrough, an inlet adapted to connect to said second end of thetube, and an outlet adapted to connect to a second end of the catheter.16. The hemodialysis and vascular access system of claim 1, wherein saidsystem further comprises at least one needle having a first endconfigured to couple to a hemodialysis device and a second end adaptedfor insertion directly into said tube.
 17. A hemodialysis and vascularaccess system to shunt blood between a vein and an artery, said systemhaving a single lumen comprising: a tube having first and second ends,said first end adapted to be anastomosed to said artery; and a catheter,comprising tubing having a first end and a second end, said second endbeing connected to said second end of said tube; said catheter having asite for entering said vein, said site being away from said first end ofsaid catheter so that, in use, said first end can be located downstreamin said vein; and needle receiving sites between said first end of saidtube and said first end of said catheter; said tube and said catheterbeing adapted to be entirely subcutaneous in use and configured toavoid, in use, a blood reservoir therein and to provide continuous bloodflow.
 18. The hemodialysis and vascular access system of claim 17,wherein said first end of the catheter is adapted for percutaneousinsertion in said vein.
 19. The hemodialysis and vascular access systemof claim 17, wherein said first end of the catheter is beveled.
 20. Thehemodialysis and vascular access system of claims 17, wherein saidsecond end of the catheter comprises an enlarged portion configured tolock with said second end of the tube.
 21. The hemodialysis and vascularaccess system of claim 17, wherein said system further comprises acoupler adapted to join said second end of the tube to said second endof the catheter.
 22. The hemodialysis and vascular access system ofclaim 17, wherein said second end of the tube is glued to said secondend of the catheter.
 23. The hemodialysis and vascular access system ofclaims 1, wherein said catheter comprises a cuff adapted for sewing tothe vein.
 24. The hemodialysis and vascular access system of claim 1,wherein said catheter comprises multiple layers of material.
 25. Thehemodialysis and vascular access system of claim 24, wherein at leastone layer is a thrombus resistant coating.
 26. The hemodialysis andvascular access system of claim 24, wherein said catheter furthercomprises an inner layer of PTFE material and an outer layer of silasticmaterial.
 27. The hemodialysis and vascular access system of claim 17,wherein the material of said tube and said catheter comprise PTFE. 28.The hemodialysis and vascular access system of claim 17, wherein thematerial of said tube is PTFE and the material of said catheter issilastic.
 29. The hemodialysis and vascular access system of claim 17,further comprising a needle receiving site between said first and secondends.
 30. The hemodialysis and vascular access system of claim 29,wherein the needle receiving site comprises a frame having a passageextending therethrough, an inlet adapted to connect to said firstportion of the tube, an outlet adapted to connect to said second portionof the tube.
 31. The hemodialysis and vascular access system of claim17, wherein said system further comprises at least one needle having afirst end configured to couple to a hemodialysis device and a second endadapted for insertion directly into said system.
 32. A hemodialysis andvascular access system, comprising: an arterialized indwelling venouscatheter having a first portion provided from a material which isbiocompatible with an arterial system, has a nonthrombogeniccharacteristic, which is adapted for attachment to an arterial systemand a catheter section, with a first end of said first portion adaptedto be coupled to an arterial system and a portion of the cathetersection adapted to be inserted within a venous system at an insertionsite, said catheter section portion having an outside diameter which isless than an inner diameter of the venous system and having at least oneopening in an end thereof with at least one of the at least one openingsin the catheter section portion adapted to be within the venous systemitself and wherein the at least one opening is distant from theinsertion site such that, in operation, blood flows from the arterialsystem through the catheter and is returned to the venous system throughthe at least one opening and blood also flows through the veinuninterrupted around at least an outer portion of said catheter; and atleast one needle having a first end coupled to a hemodialysis device andhaving a second end adapted for insertion directly into the arterializedindwelling venous catheter to shunt the blood flow through the dialysisdevice.
 33. The hemodialysis and vascular access system of claim 32wherein the first portion of said arterialized indwelling venouscatheter is provided from a first tube and said catheter section isprovided from a second tube comprising multiple layers and a first endof said first tube is coupled to a first end of said second tube. 34.The hemodialysis and vascular access system of claim 33 wherein saidfirst and second tubes are adapted for percutaneous placement.
 35. Thehemodialysis and vascular access system of claim 33 wherein the end ofsaid second tube which is coupled to the first tube includes an enlargedportion in which the first end of said first tube is disposed.
 36. Ahemodialysis and vascular access system as in claim 32, wherein thefirst portion comprises PTFE.
 37. A hemodialysis and vascular accesssystem as in claim 32, wherein the first portion has a diameter ofapproximately 7 mm.
 38. A hemodialysis and vascular access system as inclaim 32, wherein the first end of the first portion has a diameter ofabout 4 mm.
 39. A hemodialysis and vascular access system as in claim32, wherein the catheter section comprises a silastic material.
 40. Ahemodialysis and vascular access system as in claim 32, wherein thecatheter section comprises silicone.
 41. A hemodialysis and vascularaccess system as in claim 32, wherein a downstream end of the cathetersection is provided with a bevel.
 42. A hemodialysis and vascular accesssystem as in claim 32, additionally comprising an access segment forreceiving a needle to allow access to blood flowing through thecatheter.
 43. A hemodialysis and vascular access system as in claim 33,wherein the access segment comprises a self sealing material.
 44. Ahemodialysis and vascular access system as in claim 43, wherein the selfsealing material comprises silicone.
 45. A hemodialysis and vascularaccess system as in claim 43, wherein the access segment is removablyconnected to the access system.
 46. A hemodialysis and vascular accesssystem as in claim 43, further comprising a frame in the access segment.